Appropriate composites of cefoperazone-sulbactam against multidrug-resistant organisms Chih-Cheng Lai,1 Chi-Chung Chen,2,3 Ying-Chen Lu,3 Tsuey-Pin Lin,4 Yin-Ching Chuang,2,5 Hung-Jen Tang4,6 1Department of Intensive Care Medicine, Chi Mei Medical Center, Liouying, 2Department of Medical Research, Chi Mei Medical Center, Tainan, 3Department of Food Science, National Chiayi University, Chiayi, 4Department of Health and Nutrition, Chia-Nan University of Pharmacy and Science, 5Department of Internal Medicine, Chi Mei Medical Center, Liouying, 6Department of Medicine, Chi Mei Medical Center, Tainan, Taiwan Objectives: This study aims to assess the in vitro activity of different cefoperazone–sulbactam ratios against different multidrug-resistant organisms (MDROs).Materials and methods: Minimum inhibitory concentrations (MICs) and susceptibility rates of cefoperazone, sulbactam and cefoperazone–sulbactam at fixed ratios of 2:1, 1:1 and 1:2 against 344 MDRO clinical isolates, including extended-spectrum β-lactamase (ESBL)-producing Escherichia coli